ARlogo Annu. Rev. Astron. Astrophys. 1999. 37: 445-486
Copyright © 1999 by Annual Reviews. All rights reserved

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5. COSMOLOGY

Hubble had outlined his vision of cosmological research with the Palomar telescopes in his 1951 Penrose lecture. His principal plans concerned four programs:

  1. the large scale distribution of galaxies
  2. the law of redshifts
  3. the cosmic distance scale
    1. Cepheid P-L relation
    2. distance to M31
    3. novae as distance indicators
    4. distances to M81 group and M101 group galaxies
    5. the "average" galaxy as a statistical distance indicator
    6. brightest stars
    7. brightest galaxies in clusters
  4. Cosmological theory

Many of these programs have eventually been carried to completion, yet the final solution of the distance scale remains at this writing in contention, even if only at the 25 percent level.

Other programs not mentioned by Hubble but which have also been central to the Palomar work concern Galaxy morphology as it relates to galaxy formation and evolution. Here Baade's population concept has become intertwined with Hubble's purely geometrical cosmology. (3)

In particular, the problem of the earliest stages of galaxy formation, not even conceived in the 1930s, is now centered on studies of the Lyman alpha forest that was seen in high dispersion quasar spectra, detected at sufficient spectral resolution by Weymann et al (1981). Many Palomar studies followed, where the telescope was host to the efficient instrumentation developed by the UK group led by Boksenberg and used in many collaborations with Caltech astronomers. Important reviews include those by Weymann (1993), Lanzetta (1993), Bajtlik (1993), Boksenberg (1995), Rauch (1998).

How much of Hubble's program has in fact been completed?



3 Baade's dictum, often stated with vigor when, in his opinion, too large a fraction of the scheduled 200-inch time was being assigned to the redshift programs of Hubble and Humason, was "You will never understand the spatial geometry (world model) until you understand the galaxies that you are using as markers of the space." Back.

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